SR Receiver Filtering dialog box
The SR Receiver Filtering dialog box allows you to set up the receiver parameters in the SR type receiver units. You can apply filters to the data received from a PX TrawlEye or any other active gear monitoring sensor on the sensor list.
Prerequisites
The SR Receiver Filtering functions are only available for SR type receiver units:
•  Simrad SR15
•  Simrad SR70
Image
How to open
This dialog box is opened from the Operation menu.
Image
Description
Use the SR Receiver Filtering functionality to minimize the interference from other acoustic systems (sonars and echo sounders) on your own and/or other vessels. The filter also suppresses noise from your propellers, and from other similar noise sources. The four filter settings are used to control the "efficiency" of the filter. To disable the filter, set it to Off.
Details
Interference Filter
The Interference Filter removes noise and false echoes from other echo sounders and sonars in the vicinity of your vessel. This is a median filter.
When you operate in areas with substantial reverberation due to the bottom conditions, or in shallow waters, you may experience “jumps” or spikes in the data received from the sensors. Such errors can also be caused by other types of hydroacoustic equipment operating on the same freqyency range as the TV80 system. The Multipath Filter has also been implemented to remedy for such interference problems.
The Interference filter offers four different settings. The default setting of the filter is Weak.
•  In Off mode, the filter is disabled.
•  In Weak mode, the data from the last three sensor transmissions are median filtered.
•  In Medium mode, the data from the last five sensor transmissions are median filtered.
•  In Strong mode, the data from the last seven sensor transmissions are median filtered.
Sensor Filter
The Sensor Filter can be used if you have problems with the reception. It will average the data received from the sensors. After the sensors have been submerged, the receiver requires only three consecutive pings from individual sensors to calculate and display their respective information. However, if you experience problems with the reception, you may try this filter.
The Sensor filter offers four different settings.
•  Off
The Sensor filter is switched off.
•  Weak
The information from the last four sensor transmissions are averaged.
•  Medium
The information from the last eight sensor transmissions are averaged. This has proven to be a useful setting for trawlers.
•  Strong
The information from the last 16 sensor transmissions are averaged.
The default setting of the filter is Weak.
Catch filter
This is a median filter. The Catch filter reduces the jumping between “catch” and “no catch” states. This will reduce jitter in the presentation.
The Catch filter offers four different settings. The default setting of the filter is Weak.
•  In Off mode, the filter is disabled.
•  In Weak mode, the data from the last three sensor transmissions are median filtered.
•  In Medium mode, the data from the last five sensor transmissions are median filtered.
•  In Strong mode, the data from the last seven sensor transmissions are median filtered.
Catch/Bottom Filter
This is a median filter. The Catch/Bottom Filter is used to restrict the change of state from the catch and bottom contact sensors. This will reduce jitter in the presentation.
The default setting of the filter is Weak.
•  In Off mode, the filter is disabled.
•  In Weak mode, the data from the last three sensor transmissions are median filtered.
•  In Medium mode, the data from the last five sensor transmissions are median filtered.
•  In Strong mode, the data from the last seven sensor transmissions are median filtered.
Noise level
The Noise level refers to the common or general noise level picked up by the hydrophone. When noise appears in the same frequency range as the sensors are using for their communication, the resulting information may be unstable or unreadable. The graph in the Spectrum dialog box provides you with information about the background noise and the signal strength in the selected frequency band.
•  Select Low if the signal level from your sensors is high in comparison to the general noise level.
•  When the signal level of the sensors installed is not significantly higher than the general noise level, then you can select High. By selecting High you are increasing the range of detection if you are operating at the limit of the expected detection range. However, you are more sensitive to interference.